This invention relates to the packaging of springs. More specifically, this invention relates to a method of roll-packing plural spring units.
At the present time, most mattress spring core assemblies are manufactured by a spring company and then compressed and shipped in a crate to a mattress manufacturer, who then uncrates the spring cores, applies a primary insulator to the top and bottom surfaces of the mattress, and then applies conventional padding and upholstery to complete the mattress. In order to keep the mattress springs straight and avoid the mattresses top and bottom surfaces being permanently canted and distorted as the springs are compressed for shipment in a crate, there are rods inserted through the springs during the compression process. These rods function to prevent misalignment of the top and bottom surfaces of the springs during compression, which rods are then removed after compression and during shipment within the crate.
As an alternative to compression of the springs for shipment in crates, some spring assemblies are compressed and roll-packed while sandwiched only between separator plies of paper or plastic, which paper or plastic may be either discarded or reused, depending on the nature of the separating materials.
For instance, it is known in the art to pack spring units for use in making mattresses by winding disposable paper or re-usable hessian around a mandrel and feeding the spring units successively into the nip between the growing roll and the traveling web material. The spring units are compressed as they are drawn into the roll, and the result is that the roll-packed springs have a much reduced volume as compared to conventionally stacked spring units.
One type of machine known for this purpose has a winding mandrel to which a holding bar is bolted by its ends for holding the leading end of a packing web material. An upwardly moveable pressure roller is mounted above the mandrel so as to define therewith an entry nip for the web material. The web material is fed from a reel supported at the rear of the machine over the pressure roller and on to the mandrel. An operator standing at the front of the machine feeds springs into the entry nip.
Another machine for packing bedding springs is seen in U.S. Pat. No. 4,669,247. The ""247 patent describes packing spring units into a roll with a web of disposable paper or reusable material. A similar spring packing machine is seen in U.S. Pat. No. 2,114,008, in which a roll of disposable wrapping paper is fed along a table and into a wrapping mechanism whereat spring assemblies are placed upon the paper and fed into the machine by the paper movement.
All of these prior art machines compress and wrap springs in a single web of disposable paper or reusable material which separates the multiple layers of spring units in a roll and maintains the springs in a compressed state for shipment from a spring manufacturer to a mattress manufacturer. The mattress manufacturer then must apply and attach an insulated pad to at least the top and usually the top and bottom of the spring unit before adding conventional padding and upholstery to the unit to complete the mattress.
It has been one objective of the present invention to facilitate and ease the manufacture of spring mattresses by the mattress manufacturer.
It has been a further objective of the present invention to provide a method of roll packaging spring units in which the spring units are packaged in part with insulator material that becomes part of the mattress and is used by the mattress manufacturer in mattress production.
It has been yet another objective of the present invention to provide a series of roll packed spring units in which the insulator material is permanently applied to the spring units either as a part of or before the roll packing of the spring units.
The preferred embodiments of the present invention accomplish these objectives with a method of packaging a plurality of resilient spring units each comprising a plurality of interconnected coil springs. First and second webs of spring insulator material are attached to the spring units so as to be located against top and bottom surfaces of the spring units. The spring units with the webs of insulator material permanently attached thereto are thereafter roll-packed for shipment from a spring manufacturer to a mattress manufacturer who simply unrolls the spring units and, if the insulator material had not been previously cut between spring units prior to roll packing, cuts the insulator material between the spring units and proceeds to complete the mattress by adding conventional padding and upholstery.
Each spring unit has a uniform depth defined by a generally planar top or first surface and a parallel generally planar bottom or second surface. The spring unit has a longitudinal dimension or length defined by a pair of opposed parallel end surfaces and a transverse dimension or width defined by a pair of opposed parallel side surfaces. The longitudinal dimension or length is generally greater than the transverse dimension or width of the spring unit as in most bedding products. However, a square spring unit in which the longitudinal and transverse dimensions are equal may also be packaged using this inventive method.
The method of the present invention includes providing a first and usually first and second web rolls of insulator material spaced from one another. The first web roll includes a first web of spring insulator material, e.g., woven or non-woven material, wound about a core. Similarly, the second web roll includes a second web of spring insulator material wound about a core. Each of the first and second webs of insulator material have a pair of opposed side edges defining a width of the web which is wider than the transverse dimensions of the spring units. Each web across its width has a pair of opposed side portions and a central portion between the side portions.
The first web of insulator material is passed over and located against the first surface of the spring unit, and the second web is passed under and located against the second surface of the spring unit. The longitudinal dimension of the spring unit is generally parallel to the opposed side edges of the first and second webs which are generally parallel to one another.
In a first preferred embodiment, the first and second webs are folded back upon themselves around the top and bottom turns of the edgemost coil springs of the spring unit so that the opposed side portions are located against the surface of the central portion located against the spring unit. These side portions are then bonded, welded or otherwise secured to the central portion.
In a second preferred embodiment, the side portions of the first web are bonded or welded to the adjacent side portions of the second web so as to form a tight fitting sleeve in which the spring unit is securely located. The spring unit with the first and second webs secured there against constitutes a bedding product.
The bedding product having the insulator material permanently attached thereto is inserted into a roll packing machine in which the bedding product is compressed and rolled onto a dowel or mandrel whereafter the bedding product is maintained in this rolled and compressed state for shipment to a mattress manufacturer.
In one embodiment of the present invention, after the insulator material is applied to the first and second surfaces of the spring unit, additional separator packing material such as paper or sheet plastic is used to separate layers of rolled bedding product. In particular, first and second webs of separating material are located against respective first and second webs of insulator material. As the bedding products are roll-packed, the first and second webs of separating material further package the series of bedding products. Then, in both the first and second embodiments of the present invention method, the series of packaged bedding products formed by the spring manufacturer is thereafter shipped to the mattress manufacturer. The series of roll-packed bedding products is then unrolled by the mattress manufacturer and, if the webs of insulator material had not been severed prior to roll packing, are severed into separate bedding products with the insulator material still applied to each spring unit so that the mattress manufacturer may use the permanently attached insulator material in the manufacture of a mattress.
As an alternative to the use of two webs of separating material located against first and second webs of insulator material during the roll packing of the bedding product having the insulator material permanently applied to at least one surface thereof, only one web of separating material may be utilized. In this event or embodiment, the web of separating material is first attached to the dowel or mandrel by having at least one wrap of the separating material applied to the dowel or mandrel after which the bedding products are sequentially fed into the nip between the dowel or mandrel and the web of separating material. The separating material then functions to maintain the roll packed bedding products in a compressed state and separated one from the other as they are rolled up through multiple plies or layers onto the dowel or mandrel. After an appropriate number of bedding products have been roll packed onto the dowel or mandrel, the single web of separating material is then wound about the exterior of the roll of roll packed bedding products and taped or glued or otherwise secured to the exterior of the pack to complete the roll pack. This roll pack is then shipped to the mattress manufacturer where the roll pack is unrolled by the manufacturer and the web or webs of insulator material are severed between separate bedding products if the web or webs of insulator material had not been severed prior to insertion of the bedding products into the roll packing machine. That mattress manufacturer then uses the bedding products having the insulator material already permanently attached to the spring units to manufacture a mattress by simply applying conventional padding and upholstery to the bedding product.
These and other objectives and advantages of this invention will be readily apparent from the following description of the drawings.